Foot and Mouth Disease is caused by a highly contagious virus that spreads rapidly in cattle, pigs, goats, and sheep. It causes large vesicles (blisters) in the mouth and around the hooves, but does not have a high mortality. (2-5% in most outbreaks, aside from one in Taiwan in 1997 that had near 100% mortality and only affected pigs.) However, the pain associated with the lesions is great, often resulting in lameness and anorexia, which leads to very poor condition, greatly decreasing the animal’s value. Recovery is slow and, accounting for time and extra feed spent bringing the animal back up to a selling weight, very expensive. Because of this economic loss, the most cost-worthy option, and the standard protocol for most of the world is to kill the entire herd to prevent spread, and cut your losses at that.
A vaccine is available, but it makes screening for the virus impossible, because our detection of FMD is based on whether or not an animal is seropositive (has antibodies) for the virus. The vaccine mimics the virus, creating a response that shows as a false positive during screening. Screening happens in import/export situations to make sure a country without FMD is not importing cattle that have FMD. Thus, vaccinated animals cannot be exported, and if an animal is positive on screening, it and any animals at risk (any animals near that one) need to be euthanized. What’s more, the country where that animal is from is labeled as FMD positive, and there will be no exports accepted from there until that country is able to prove that they do not have the disease anymore (all animals are seronegative). This can quickly become a terrible economic problem.
Such is the case in Botswana right now. There is a “red zone” in the north of the country where wild buffalo reside. Buffalo are natural reservoirs for FMD, it will multiply in them and spread from them, but not harm them. Therefore, any cattle from that red zone are vaccinated there to prevent infection, and they cannot be moved out of the red zone or sold to other countries. However, from the green zone, Botswana has historically had a strong partnership selling beef to Europe, a significant portion of the national income. That was, until about February of this year. Zimbabwe, unlike Botswana, does not limit the interactions of its cattle with buffalo, allowing frequent outbreaks of FMD in the country. They have had a continuous bad run of FMD since about 2005.
Normally, a buffer of vaccinated non-exported cattle is kept between Botswana and Zimbabwe, but FMD still managed to spill over across the border into Botswana in early May 2011, potentially from illegal animal trafficking, near Francistown in the northeast. Feed lots and export abattoirs were immediately shutdown and Europe put a ban on Botswana meat imports until the green zone is again FMD free, crippling the meat industry in Botswana (run by the Botswana Meat Commission) for the past month. The disease continues to spread in the northeast, and until it is under control, there will be no more exports and the feedlots will remain closed. In order to get things running again, an OIE (World Organization for Animal Health) inspection must find the area FMD free. All viral infection must be stopped, and all vaccinated animals must be slaughtered for local consumption only, as in the red zone up north.
This is a big area of concern here; I’ll report more as the situation develops. FMD rarely affects humans, is unrelated to human Hand, Foot, and Mouth Disease, and USA has been FMD free since the 1920s.